The strain of connecting reinforcement versus shear load relationship was analyzed, based on an experimental study on double-superimposed shear wall horizontal connections subjected to reversed cyclic shear deformations combined with vertical loads. The results showed that the variation trends of connecting reinforcement strain in double-superimposed shear wall horizontal connections were identical with that in cast-in-place horizontal connections. The shear mechanism of double-superimposed shear wall horizontal connections was analyzed based on shear-friction theory, the ultimate shear capacity of the double-superimposed shear wall horizontal connections was determined by the bond force at the interface, the interface friction and dowel action of shear connecting reinforcement. The proposed calculation formula for shear bearing capacity of the double-superimposed shear wall horizontal connection was derived based on the shear-friction theory.